For example, in a known technique, a system includes a personal computer (“PC”), a relay device, a multifunction peripheral (“MFP”), and a service providing device. The PC transmits a temporary registration ID issue request to the relay device. Upon receipt of the temporary registration ID issue request, the relay device generates a temporary registration ID and transmits the temporary registration ID to the PC. Thus, the PC displays the temporary registration ID thereon. A user inputs the temporary registration ID displayed on the PC into the MFP by operating the MFP. Upon receipt of the temporary registration ID, the MFP transmits the temporary registration ID to the relay device. Upon receipt of the temporary registration ID, the relay device acquires an access token from the service providing device using the temporary registration ID. In the known technique, the user may need to operate the MFP to input the temporary registration ID into the MFP.